Synthesis and photophysical properties of novel benzophospholo[3,2-b]indole derivatives

• Mio Matsumura,
• Mizuki Yamada,
• Atsuya Muranaka,
• Misae Kanai,
• Naoki Kakusawa,
• Daisuke Hashizume,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2017, 13, 2304–2309, doi:10.3762/bjoc.13.226

• , Japan Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan 10.3762/bjoc.13.226 Abstract The parent benzophospholo[3,2-b]indole was prepared by the reaction of dichlorophenylphosphine with a dilithium intermediate, which was prepared in two steps from 2-ethynyl-N,N

• tetracyclic moieties are planar. The benzophosphole-fused indoles, such as phosphine oxide, phospholium salt, and borane complex, exhibited strong photoluminescence in dichloromethane (Φ = 67–75%). Keywords: benzophospholo[3,2-b]indole; DFT calculation; molecular structure; phosphole derivatives

• Scheme 1. The key precursor 2 was synthesized by I2-mediated electrophilic cyclization of 2-ethynyl-N,N-dimethylaniline 1 [36][37]. Treatment of compound 2 with n-butyllithium in anhydrous THF at −78 °C and subsequently with PhPCl2 resulted in ring closure, affording the desired benzophospholo[3,2-b